1. Field of the Invention
The present invention relates to a bicycle and more particularly, to a rear frame for a bicycle, which has a high mechanical strength and light weight.
2. Description of the Related Art
The rear part of the frame of a bicycle includes seat stays and chain stays. The seat stays and the chain stays have a similar structure, i.e., both include two tubes approximately parallel to each other and a connecting portion connected between the two tubes. In order to reduce the weight of the seat stays or chain stays, carbon fiber reinforced materials are used. The seat stays and the chain stays are set to support the rear wheel after installation. Therefore, the seat stays and the chain stays must bear the vibration of the rear wheel. Frequently receiving the vibrating force from the rear wheel may cause the seat stays and the chain stays to deform or to break. In order to improve the structural strength, the consumption amount of carbon fiber cloth must be increased. However, increasing the consumption of fiber cloth correspondingly increases the weight of the seat stays and the chain stays.